A case of primary aldosteronism with excessive secretion of renin that was unmasked by kidney transplantation.

A 42-year-old man showed marked hypokalemia after kidney transplantation. He was diagnosed with hypertension and suffered from acute myocardial infarction at 33 and 38 years of age. At 40 years of age, hemodialysis was introduced. A left adrenal tumor was noted and suspected as a non-functional adrenal adenoma at that time. Therefore, he received a living-donor kidney transplant at 42 years of age. After kidney transplantation, the serum creatinine level dropped. His blood pressure remained high, and the serum potassium level decreased. The PRA and PAC were elevated, and ARR was not elevated. Based on the results of various confirmatory tests and vein sampling, he was diagnosed with excessive secretion of renin from the native kidneys that was complicated by primary aldosteronism (PA), and left nephrectomy and adrenalectomy were performed. The overproduction of aldosterone in the resected adrenal adenoma and over secretion of renin in the kidney with arteriolosclerosis were immunohistologically confirmed. After surgery, the PAC decreased, but the PRA did not decrease. The postoperative serum potassium level improved, and the blood pressure was well controlled with a small dose of medication. This is the first reported case of PA with hyperreninemia after kidney transplantation. It should be noted that PA in dialysis patients and kidney transplant recipients may not fulfill the usual diagnostic criteria of an elevated ARR. In such patients, PA should be suspected based on the absolute value of the PAC and responsiveness to ACTH stimulation, and adrenal and renal vein sampling is required for a definitive diagnosis.

A case of primary (AL) amyloidosis with predominantly vascular amyloid deposition in the kidney.

We report a 70-year-old man with primary (AL) amyloidosis with predominantly vascular deposition of amyloid diagnosed by renal biopsy, who was successfully treated using two chemotherapy regimens. There was rapid elevation of the serum creatinine level without remarkable proteinuria or hematuria. Renal histological examination showed some thickened arterial walls with amyloid fibril accumulation, and only a small amount of amyloid deposition in the glomeruli. Immunohistochemical examination was positive for anti-kappa staining. Serum immunoelectrophoresis and immunofixation testing did not show monoclonal proteins, and urine immunoelectrophoresis did not show Bence-Jones proteins. Serum free light chain (FLC) analysis showed that the serum FLC level and FLC kappa/lambda ratio were abnormally high for his renal function. He received two courses of VAD (vincristine, doxorubicin, and dexamethasone), followed by BD (bortezomib and dexamethasone), resulting in a hematologic partial response. Renal amyloidosis with vascular-limited amyloid deposition has few urinary findings. Early diagnosis of this condition is challenging, because kidney biopsies are not usually performed in patients without significant urinary findings. We suggest several currently available methods of achieving earlier detection of this condition.